Contact and Momentum Distribution of the Unitary Fermi Gas

R. Rossi (1) , T. Ohgoe , E. Kozik , N. Prokof'Ev , B. Svistunov , K. van Houcke (1) , Felix Werner (2)

1 LPS - Laboratoire de Physique Statistique de l'ENS
2 LKB (Lhomond) - Laboratoire Kastler Brossel

A key quantity in strongly interacting resonant Fermi gases is the contact C, which characterizes numerous properties such as the momentum distribution at large momenta or the pair correlation function at short distances. The temperature dependence of C was measured at unitarity, where existing theoretical predictions differ substantially even at the qualitative level. We report accurate data for the contact and the momentum distribution of the unitary gas in the normal phase, obtained by bold diagrammatic Monte Carlo and Borel resummation. Our results agree with experimental data within error bars and provide crucial benchmarks for the development of advanced theoretical treatments and precision measurements.

Mots clés: Ultracold Fermi gases; BEC-BCS crossover; Quantum Monte Carlo; Diagrammatic expansion

Domaines: Physique Nucléaire Théorique [nucl-th]; Physique Générale [physics.gen-ph]; Informatique [cs]

R. Rossi, T. Ohgoe, E. Kozik, N. Prokof'Ev, B. Svistunov, et al.. Contact and Momentum Distribution of the Unitary Fermi Gas. Physical Review Letters, 2018, 121 (13), pp.130406. ⟨10.1103/PhysRevLett.121.130406⟩. ⟨hal-01891386⟩